1. Field of the Invention
This invention relates to the field of networked computers. More specifically, it relates to a system and method to determine the geographic location of a network user based on that user's current network (e.g., Internet Protocol (IP)) address and previously stored mapping request information obtained from related network addresses.
2. Background
The Internet and personal computers have become ubiquitous in modern society. People regularly access the Internet via personal computers and other devices for any number of purposes. Traditionally, most home and small business computer users have accessed the Internet via a modem plugged in to a telephone line that connects an Internet user to an Internet service provider (ISP). It is through the ISP that the Internet user receives an IP address and accesses the Internet.
At any given moment, each Internet host is uniquely identified by an Internet Protocol (IP) address and a domain name. The format of an IP address is a 32 bit numeric address which is expressed as four integer numbers, each separated by a dot, commonly referred to as dotted-decimal notation. Each number must be in the range from zero or one to 255; the first byte cannot be zero. For example, 209.1.25.249 is a valid IP address. It is the IP address that is used by underlying network software to identify a personal computer and other network hosts that communicate over the Internet.
Though the Internet Protocol has absolute requirements regarding the nature of the dotted decimal notation and how specific addresses become associated with specific pieces of network equipment, as a matter of practice, the organizations responsible for their allocation do so in substantial blocks of addresses. For example, when an ISP requests additional address space, the ISP normally receives a contiguous range of monotonically ascending addresses, rather than a totally random assortment of unrelated addresses. This administrative mechanism leads to the following result: addresses that differ only in the least significant, forth byte of the 32 bit address are almost always on the same local area network, and consequently, are physically located within a relatively short distance, such as a mile or so, from one another.
Prior art techniques exist that rely on indirect means to essentially guess the physical location of network devices based upon their IP address. For example, a utility called “whois” allows an Internet user to find out information about domain names and IP addresses including to whom the domain name and IP address is registered. Another utility called “tracert” allows an Internet user to trace the route of a data packet from the user to a remote host specified by the user. Yet another utility called “nslookup” allows an Internet user to look up the IP address of a domain name. In addition, there is a tool that provides the latitude and longitude of the geographic location of an Internet host. This tool, called “ip211,” converts an IP address to latitude and longitude based on “whois” database information. More specifically, the city of the administrative contact for the IP address is obtained from a “whois” database and then converted into latitude and longitude. The address of the administrative contact is the mailing address of a party responsible for registration of the IP address and any associated domain name. This address may be geographically distant from the equipment over which the party has control, since one person can efficiently serve as the contact for nationally or globally distributed network equipment. Information regarding “ip211” is available from the Digital Computer Laboratory, Department of Computer Science, University of Illinois at Urbana-Champaign, 1304 West Springfield Avenue, Urbana, Ill. In contrast, network users are almost always physically located near network equipment accessed by local telephone calls to an ISP, as long distance telephone calls are expensive. No tools are currently available that allow an Internet user to be associated with a defined geographical area.